Claire Paris, Rosenstiel: Exposure to Solar Radiation

COMPASS 2024-10-11: Claire Paris-Limouzy, Rosenstiel School
"A Coupled ESM-Lagrangian Modeling Framework for Quantifying the Exposure to Solar Radiation in Biotic and Abiotic Particles Moving in the Ocean"
Sunlight irradiance is a source of energy for life on Earth but it can also be a stressor at high doses of UV radiation. Solar radiations also affect chemical pollutants by enhancing the photooxidation of oil and increasing the fragmentation and photodegradation of plastics in the ocean. Irradiance varies spatially, temporally, and with water bio-optical characteristics and is expected to increase with the climate crisis. To better manage solar radiation and predict its effects with climate change, we need to understand how light-related processes affect the ocean ecosystems. The first step is quantifying radiation exposure on living and non-living particles. So far, current irradiance exposure estimates have neglected the advection by the ocean and the movement of particles due to their biological or physicochemical traits. Here we present a novel Irradiance Module developed to quantify the cumulative UV radiation exposure on active particles. The module coupled the open-source Connectivity Modeling System (CMS) to the net surface shortwave radiations from the NAVy Global Environment Model (NAVGEM). Case scenario simulations of zooplankton and microplastics in the global ocean show that the cumulative doses of irradiance received by particles are primarily determined by their 3D pathways rather than by the irradiance reaching the ocean’s surface. With the particles' motion behavior overlooked, the fine scale light-related processes affecting them remains invisible. Several biological, chemical, and physical applications may emerge from this solar irradiance modeling framework.